Research on Controllable Synthesis of Magnesium Carbonate Tri-Hydrate

Abstract

In order to promote the comprehensive utilization of salt lake brine resources, magnesium carbonate tri-hydrate (MgCO3·3H2O) was synthetized by low-temperature hydrothermal technique using purified MgCl2-rich brine and ammonium hydrogen carbonate solution as raw materials, the orthogonal experimental as method. The morphology could be tuned by changing the operating parameters. X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to characterize the structures and morphologies of the products. The results show that the optimum conditions are as follows : reaction temperature is 40-50°C, n (Mg2+):n (HCO3-)=1:2.2, pH value is 8.8-9.0, stirring speed is 130 r/min, aging time is 3h, reaction time is 70 min. Magnesium carbonate tri-hydrate synthetized is one-dimensional acicular with good settling performance. Average aspect ratio could up to 29.60.